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by Sleepless on LI » Sun Oct 02, 2005 10:33 am
Yes, feel free to call me "sweetie." That is just fine.
The problem is, you're talking about BiPAP, which according to my son is totally more involved than CPAP. CPAP is only setting an end pressure upon exhalation. Please look at the link I provided at the bottom of the post. Your doctor was not incorrect. But he was regulating your breath so that it won't go over a certain amount on inhalation and a lesser amount in exhalation due to him feeling you need more of a ventilation type therapy than CPAP/PEEP, if I'm remembering now, a couple of hours later, what my son explained.
The two terms PEEP and CPAP are used interchangeably, and lead to inappropriate confusion: they are the same thing, although CPAP is a more technically correct term. The concept of PEEP is that a pressure is applied at the end of expiration to maintain alveolar recruitment (click here). Airway pressure is kept positive, and is never allowed to return to atmospheric (click here). When inspiration commences, it is on top of this the pressure that remains in the airway at the end of expiration – this is the baseline airway pressure (below which it cannot go) and lasts for the duration of the respiratory cycle (regardless of the inspiratory mode of ventilation). Therefore, all patients who have a resistance applied to expiration (to prevent derecruitment) are on CPAP. Nevertheless, it is conventional to describe this mode as PEEP, and this is what you will read in books and journals. The current thinking on CPAP is that the level set should be above the lower inflection point of the pressure volume curve (labeled Pflex in figure below), although this is controversial (click here). An easier strategy is to base PEEP on Oxygen requirements (click here).
When people have further problems other than just OSA, they are put onto BiPAP so both iPAP and ePAP get regulated specifically. It is for pulmonary problems, according to what my son says, or people who have trouble with breathing, not just OSA.
I sent your remarks to his email address; however, since he worked a 12 1/2 hour shift last night, he is sleeping today until about 5 PM. He's going in again tonight. I will try to get his reply to your question before he goes. I'm sure he'll have one. But in the meantime, please look at the link I put at the bottom of my last post which shows that PEEP is synonymous with CPAP. They are both settings for ePAP only. And that's what CPAP is if it's synonymous with PEEP. You can inhale as much as your lungs can tolerate on CPAP because, if you think about it, pushing air into your nose is not going to stop you from inhaling, is it? But it's the exhale that causes the problem, so they will titrate you at the least amount of pressure possible upon exhalation to stop the airways from closing up.
I don't know. It makes sense to me. But I will talk to him later and see his specific explanation and get back to you.
Last edited by
Sleepless on LI on Sun Oct 02, 2005 10:38 am, edited 1 time in total.
L o R i
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